Lazy males? Bioenergetic differences in energy acquisition and metabolism help to explain sexual size dimorphism in percids

摘要: 1. Differences in energy use between genders is a probable mechanism underlying sexual size dimorphism (SSD), but testing this hypothesis the field has proven difficult. We evaluated as an explanation for SSD two North American percid species - walleye Sander vitreus and yellow perch Perca flavescens. 2. Data from 47 67 populations indicated that associated with onset of maturation: typically, males both matured smaller earlier attained asymptotic than females. Males also demonstrated equal (perch) or longer (walleye) reproductive life spans compared 3. To examine whether reduced post-maturation growth was due to lower acquisition higher costs we applied contaminant mass-balance model combined bioenergetics estimate metabolic food consumption each sex. Mature exhibited consumption, conversion efficiencies 4. propose slower at maturity result decreased feeding activity reduce predation risk. Our finding percids supported by laboratory-based observations reported elsewhere, showing changes rate, efficiency were elicited oestrogen (positive effects) androgen (negative exposure P. flavescens fluviatilis. 5. Researchers applying bioenergetic models comparative studies across should caution absence information on population sex ratio potential differences sexes energetic parameters.